Endometrial thickening of 17mm is mostly seen in the endometrium and can be caused by a variety of reasons and does not necessarily lead to cancer. If cancer occurs, the exact time varies from person to person and cannot be generalized. If the endometrial thickening of 17mm is clinically manifested by irregular vaginal bleeding and flowing water, and ultrasound examination indicates cystic solid echogenicity and echogenic disorder, it is considered to be a manifestation of precancerous lesion, and the diagnosis can be confirmed by scraping and endometrial examination. If the patient has endometrial thickening of 17mm, but no abnormal uterine bleeding, it is mostly considered as endometrial polyp or simple hyperplasia of endometrium, and usually no cancer will occur. Therefore, it is recommended that patients should go to the gynecology or oncology departments of regular hospitals promptly after the occurrence of the above symptoms.